Whittaker Corporation, Santa Clarita, California

We provided environmental consulting services to the owner and previous operator of a 1,000-acre former ordnance manufacturing facility in southern California. The history of this site began in the 1930s with production of fireworks and expanded to include manufacture and fabrication of ordnance components, solid fuel rocket motors, flares, smoke cartridges, and detonators. The facility had 13 RCRA units including burn and detonation units and surface impoundments. The facility was closed in 1986 and 1987 with demolition of buildings and infrastructure facilities.

After closure, contamination was detected in soil associated with one of the RCRA units. Beginning in 1989, one of our professionals was responsible for tasks associated with obtaining closure of five RCRA units. Ultimately, 12 of the 13 RCRA units were closed by the State of California (Department of Toxic Substances Control). Ground water monitoring wells and a soil vapor extraction system were installed by another consultant to investigate potential contamination in ground water and remediate soil contamination in the vadose zone at the RCRA unit. Subsequently, we were responsible for quarterly ground water monitoring reporting and assisting with soil vapor extraction operation and maintenance.

We began a full scale Remedial Investigation/Feasibility Study in 1994 and 1995 by preparing a Work Plan in accordance with Superfund and Department of Toxic Substances Control requirements to investigate contamination at 76 Solid Waste Management Units and areas of concern. We implemented the first phase of the Work Plan in 1995 and 1996 resulting in the Draft Remedial Investigation Report in January 1997.

During 1997 and 1998, we responded to the discovery of perchlorate in municipal drinking water wells near the site and the discovery of perchlorate, N-Nitrosodimethylamine and explosives (HMX and RDX) in onsite ground water monitoring wells. We conducted surface water sampling to evaluate perchlorate and other chemicals of concern in the surface water runoff flowing offsite.

During 1995 to 1999, we prepared the work plan, completed the field investigation activities, conducted negotiations with regulatory agencies, performed data reduction and validation, coordinated preparation of a draft baseline human health risk assessment and ecological risk assessment, and prepared associated reports.

We completed a large-scale soil vapor surveying program to rapidly investigate the occurrence and extent of volatile organic compounds in soil at many areas of concern. We planned the soil vapor surveys, supervised the collection of high-quality analytical data, and interpreted the analytical results to identify the volatile organic compounds of concern at each area, delineate the extent of volatile organic compounds, and plan for subsequent invasive soil sampling and analysis. The surveys included vertical profiles at selected locations and limited sampling at additional areas of concern to verify previous analytical results from soil samples. The scope of work encompassed a total of 54 areas of concern and included more than 1,600 samples from over 1,200 locations, covering a total area greater than 10 acres.

We expedited the investigation of numerous large areas of concern by applying surface geophysical technologies to minimize and focus subsequent sampling activities. The areas of concern included known landfills of uncertain extent, other areas of reported unsystematic waste disposal, and sumps beneath former buildings. The surface geophysical surveys provided data to delineate the lateral extent of waste fill areas, characterize the relative amounts of waste material in different areas of fill, and select locations for subsequent invasive investigation and sampling. The total scope of work included over 12,000 stations, most often magnetic field surveys (total field and vertical gradient) and terrain conductivity surveys (Geonics EM-31 and EM-34). We also supervised ground penetrating radar surveys performed by a subcontractor at selected locations.

Whittaker Corporation, Hollister, California

We managed and conducted the investigation of trichloroethylene detected in a water supply well at an operating ordnance manufacturing facility, worked with the client and regulatory agencies, and prepared an approved scope of work for detection and delineation of trichloroethylene in soil and shallow ground water beneath the site. We also installed and sampled monitoring wells, and designed, permitted, and installed activated carbon filtration systems to remove trichloroethylene from water pumped from numerous domestic supply wells.

When the investigation discovered trichloroethylene in nearby offsite wells, we prepared a report for the client in response to a Cleanup and Abatement Order from the RWQCB. This report included a work plan for additional soil borings and monitoring wells to assess the extent of trichloroethylene in ground water and soil underlying the site.

We assisted the client with a public notification program to inform offsite water users about impacted ground water, conducted research on uptake of trichloroethylene by agricultural crops, and had local crops analyzed for trichloroethylene. We attended public meetings with the client and area residents to discuss the current status of the investigation/remediation and potential future actions as well as alternatives for future water supply in the area.

Our team coordinated emergency installation of carbon filtration systems at nine locations serving 22 residences. In conjunction with the client and regulators, we developed alternatives for supplying potable water to domestic users. We installed an interim remediation system, including pumping to establish hydraulic control of ground water containing the highest levels of trichloroethylene. The jurisdiction's approval was obtained to allow discharge of the treated ground water to the sanitary sewer. We then supervised installation of two air strippers with more than 400- and 600-gallons per minute capacity to remove trichloroethylene from ground water pumped from agricultural irrigation wells. We obtained RWQCB approval of a work plan for installation of nested wells to assess the vertical distribution of trichloroethylene in ground water